Magnetic return device for reset timer/counter unit and reset timer/counter unit using same

IN a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means including a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel with said permament magnets being mutually balanced when said second subwheel is in said selected position, the improvement comprising:
• said first magnet being a first magnetic ring with a first generally cylindrical, radially facing pole surface with first and second opposite polarity magnetic poles extending around said first pole surface and said second permanent magnet being a second magnetic ring with a second generally cylindrical, radially facing pole surface facing said first pole surface having first and second opposite polarity magnetic poles extending around said second pole surface, said poles being in patterns where said poles of said first surface face opposite polarity poles of said second surface when said second subwheel is in said selected position, each of said first and second poles on each of said surfaces extending circumferentially approximately 180.degree..

In a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means including a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel with said permanent magnets being mutually balanced when said second subwheel is in said selected position, the improvement comprising:
• said first magnet being a first magnetic ring with a first generally cylindrical, radially facing pole surface with first and second opposite polarity magnetic poles extending around said first pole surface and said second permanent magnet being a second magnetic ring with a second generally cylindrical, radially facing pole surface facing said first pole surface having first and second opposite polarity magnetic poles extending around said second pole surface, said poles being in patterns where said poles of said first surface face opposite polarity poles of said second surface when said second subwheel is in said selected position, each of said pole surfaces including a pole terminating portion wherein said first magnetic pole is adjacent to said second magnetic pole and wherein said first and said second poles each have an axial pole width greater than the axial width of said first and said second poles at surface positions spaced from said pole terminating portion.

In a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means including a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel with said permanent magnets being mutually balanced when said second subwheel is in said selected position, the improvement comprising:
• said first magnet being a first magnetic ring with a first generally circular pole surface with first and second opposite polarity magnetic poles and said second permanent magnet being a second magnetic ring with a second generally circular pole surface facing said first pole surface and having first and second opposite polarity magnetic poles, said poles being in patterns where said poles of said first surface face opposite polarity poles of said second surface when said second subwheel is in said selected position, each of said poles being elongated and extending along an arcuate path generally concentric with said shaft, each of said pole surfaces including a pole terminating portion wherein said first magnetic pole is adjacent to said second magnetic pole and wherein at least one of said first and said second poles has a magnetic strength greater than the magnetic strength of said first and said second poles at surface positions spaced from said pole terminating portion.

In a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means including a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel with said permanent magnets being mutually balanced when said second subwheel is in said selected position, the improvement comprising:
• said first magnet being a first magnetic ring with a first generally circular pole surface with first and second opposite polarity magnetic poles and said second permanent magnet being a second magnetic ring with a second generally circular pole surface facing said first pole surface and having first and second opposite polarity magnetic poles, said poles being in patterns where said poles of said first surface face opposite polarity poles of said second surface when said second subwheel is in said selected position, each of said poles being elongated and extending along an arcuate path generally concentric with said shaft, each of said pole surfaces including a pole terminating portion wherein said first magnetic pole is adjacent to said second magnetic pole and wherein at least one of said poles has an axial pole width greater than the axial width of said first and said second poles at surface positions spaced from said pole terminating portion.

In a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means includes a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel, said permanent magnets being mutually balanced in a circumferential direction when said second subwheel is in said selected position, the improvement comprising:
• means for allowing relative axial movement between said magnets with respect to said shaft, means for mounting said magnets for magnetic attraction induced relative movement of said magnets in a first axial direction when said second subwheel is in said selected position and friction braking means engageable upon relative movement of said magnets in said first direction for damping oscillations of said magnets when said second subwheel is in said selected position.

In a reset wheel assembly for a reset counter, said wheel assembly including first and second subwheels journalled about a shaft;

• said first subwheel including means for holding said first subwheel in a selected angular position with respect to said shaft;
• said second subwheel including drive means for driving said second subwheel with respect to said first subwheel;
• and biasing means for rotating said second subwheel to a selected position with respect to said first subwheel when said drive means is deactivated, said biasing means including a first permanent magnet carried by said first subwheel and a second permanent magnet carried by said second subwheel with said permanent magnets being mutually balanced when said second subwheel is in said selected position, the improvement comprising:
• said first magnet being a first magnetic ring with a first generally cylindrical pole surface with opposite polarity magnetic poles extending around said first pole surface and said second permanent magnet being a second magnetic ring with a second generally cylindrical pole surface facing said first pole surface and having opposite polarity magnetic poles extending around said second pole surface, said poles being in patterns where said poles of said first surface face opposite polarity poles of said second surface when said second subwheel is in said selected position, and including means for mounting at least one of said rings for movement axially of said shaft between a first position when poles of one surface face opposite polarity poles of the other surface and a second position spaced axially from said first position and friction brake means engageable when said rings are in said first position for damping oscillations of said rings when said rings are in said first position.